Catch2 compatibility means the API tests are written in: the macros, such
as TEST_CASE and REQUIRE, and the Catch:: namespace. It does not mean
Catch2's build names or header paths. find_package(Catch2) found Catch3,
and a project using both frameworks met two packages, two sets of targets,
two Catch.cmake modules and two catch2/ header trees with the same names.

Build names:
- CMake: project and package Catch3, targets Catch3::Catch3 and
  Catch3::Catch3WithMain, libraries Catch3 and Catch3Main, options
  CATCH3_*, lib/cmake/Catch3 with Catch3Config, and pkg-config catch3 and
  catch3-with-main. The version is Catch3's, 0.3.0, compatible within a
  minor version.
- The CMake scripts are Catch3.cmake (catch3_discover_tests),
  Catch3AddTests.cmake and Catch3ShardTests.cmake
  (catch3_add_sharded_tests); the helpers they define at ctest time have a
  catch3_ prefix. ParseAndAddCatchTests.cmake, deprecated upstream, is gone.
- Bazel //:catch3 and //:catch3_main, Meson catch3 and catch3-with-main
  (with override_dependency), Xmake catch3 and catch3_main, Premake Catch3
  and Catch3WithMain. Visual Studio projects get GUIDs of their own.
- The Progmasoft::Catch3 target and package are gone: property testing
  and snapshots are part of Catch3::Catch3. Their sources now build with
  the library's warning flags, so property failures are built field by
  field (no missing initializers) and the default property name is a
  thread-local pointer to the name its scope owns (no global destructor).

Headers: the engine moved from src/catch2 to src/Progmasoft/Catch3 with
Progmasoft names, so <catch2/catch_test_macros.hpp> is
<Progmasoft/Catch3/TestMacros.hpp>, <catch2/matchers/catch_matchers_string.hpp>
is <Progmasoft/Catch3/Matchers/String.hpp>, and interface headers are named
after their interface, such as Interfaces/IConfig.hpp. Include guards
became #pragma once. The installed headers go to include/Progmasoft.
src/Progmasoft/Context.cpp is StrategyContext.cpp, so no two sources share
a file name.

tools/scripts/upstreamFiles.txt lists the files that come from Catch2.
The license check expects BSL-1.0 on them and Progmasoft's header on the
rest of src/Progmasoft; the convenience-header check, the amalgamation
script and the surrogate tests take the engine's headers from it. The
amalgamated files are regenerated. The header-guard workflow checks for
#pragma once instead of checkguard.

Documents, the README and the release notes describe the new names.

The underlying benchmarking machinery is templated, so that it can use
different clock implementations (either for testing, or to support user
with platform-specific clocks). However, 99.99% of all users interact
with it using the `BENCHMARK` macro, which means that they use it with
`std::chrono::steady_clock`.

By adding outlined implementation of benchmarking helpers specialized
onto `std::chrono::steady_clock`, we save some amount of time per every
TU that uses benchmarks.

Bad handling of `TestFailureException` when translating unexpected
exceptions inside assertion macros led to the unexpected exceptions
handling erroring out through throwing the same exception again.

This was then backstopped by the machinery for handling uncaught
exceptions from assertions, which is normally used by the
`CATCH_CONFIG_FAST_COMPILE` machinery, where we assume that it can
only be invoked because the assertion macros are not configured to
catch assertions.

Closes #1292

Technically we should be able to remove moveability as well, but
then we would need a larger surgery. This already improves the
compile times and binary sizes by a surprising amount.

The basic idea was to reduce the number of things dependent on the `Clock`
type. To that end, I replaced `Duration<Clock>` with `IDuration` typedef
for `std::nanoseconds`, and `FloatDuration<Clock>` with `FDuration`
typedef for `Duration<double, std::nano>`. We can generally assume that
any clock's duration can be expressed in nanoseconds, as long as we insert
`duration_cast`s into the right places.

Note that we cannot remove all dependence on `Clock` as a template
arguments, because functions that actually measure the elapsed time have
to use the Clock.

We also changed some template function arguments to pass plain function
pointers, so that the actual implementation can be placed into a cpp file.

* Split out BenchmarkInfo and BenchmarkStats to their own header
* Outline BenchmarkStats<> declaration to separate header
* Split out TestRunInfo into its own header

These changes let us remove the large `interfaces_reporter.hpp`
include from `benchmark.hpp`, and replace it with
`interfaces_capture.hpp` in `run_context.hpp`.

I also cleaned out `interfaces_repoter.hpp` from reporter headers
that depend on `reporter_common_base.hpp`. This will not change
anything in the actual inclusion set, but makes it logically
more consistent.